DRAMATIC changes to sea algae could have harmful knock-on effects
for human health and the rest of the food chain, research from Welsh
scientists has revealed.

Findings published by academics from Swansea University have
uncovered huge changes in the make-up of North Sea and North Atlantic
Ocean algae in the space of five years.

The changes seen in algal blooms - shifting from dinoflagellate to
diatom algaes - could mean a build-up of toxins on feeder organisms.

But the health repercussions for humans if they were to eat
shellfish that ingest the toxins are currently unknown.

The research also concluded that it was likely to go higher up the
food chain to impact on much larger animals, such as fish and whales.

The findings have been published in the journal Nature Climate
Change.

Professor Graeme Hays, from Swansea's Department of
Biosciences in the College of Science, and an author in the study, said:
"Imagine looking at your garden one morning and finding that the
grass had suddenly been replaced by bushes.

"This may sound far-fetched, but we have found changes of this
magnitude in the biology of the North Atlantic, with a dramatic switch
in the prevalence of dinoflagellates to diatoms - two groups which
include many of the microscopic planktonic plants forming the base of
the ocean's food chain."

The findings of Prof Hays and fellow Bioscience colleagues - PhD
students Stephanie Hinder and Emily Roberts and Professor Mike Gravenor,
along with colleagues from Plymouth University - revealed that the
change was partly driven by increases in water temperature, a well-known
symptom of global warming.

But there was the unexpected discovery that the plankton shift was
"strongly driven" by an increase in windy conditions in the
North Atlantic region over the past 50 years.

The diatoms, which appear to thrive in the windier conditions, have
increased in the last five years, while dinoflagellates have
"almost disappeared", Prof Hays said.

"This increase in windiness is something that is often
overlooked," said Prof Hays.

"In the ocean, windiness promotes vertical mixing of the
water, which in turn has profound impacts on surface nutrients levels
and the vertical distribution of plankton.

"The new patterns show major shifts in the distribution of
economically important species known to cause harmful effects through
toxin poisoning.

"The wider implications of this discovery are not fully known,
but the switch from dinoflagellates to diatoms is likely to have
propagated up the food chain to impact much larger animals such as fish
and whales.

"There is also a possible threat to human health where, for
example, biotoxins are ingested by filter feeding organisms, accumulate
within their flesh, and then are transferred higher up the food chain to
human consumption level, for example through the consumption of
shellfish."

He said that the changes in algal blooms may have serious
repercussions further up the food chain, as everything was dependent to
some extent on the base of the chain.

He said: "There has been a profound change at the bottom of
the chain, it is such a huge change that it is hard to envisage that
there could not be knock-on effects.

"Our data is a strong case pointing to the effects of changes
in the environmental conditions, and what we know about the two groups
are that they survive to very different extents in windier conditions -
diatoms do well in windy conditions, while dinoflagellates do not.

"The toxin effect is not known in great detail, as there are
'toxic' forms of both groups, and both toxic and non-toxic
forms appear to be affected the same way.

"But with toxic forms, species further up the food chain feed
on them and accumulate them.

"The most classic form of this might be for human health,
through eating shellfish such as mussels that feed on it."

CAPTION(S):

[bar] Monitoring equipment is placed in the North Sea [bar]
Scientists from Swansea University have been monitoring plankton like
eucampia zodiacus, above

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